1. Field of the Invention
The present invention relates to an image forming apparatus provided with a post-processing device and more particularly to the image forming apparatus which provides a post-processing device such as a stapling device or a punching device.
2. Background of the Related Art
The present inventors know a digital copying machine as an example of an image forming apparatus. The digital copying machine is arranged to take the steps of reading an original with a CCD (Charge Coupled Device) image sensor of a scanner, converting an analog signal of the read image into a digital signal, processing the digital signal, storing the processed digital signal in a memory, reading the image data stored in the memory if necessary, and outputting the image data to the image forming unit such as a laser printer for copying the resulting image on paper.
The present inventors also know a commercially available copying system having a post-processing device functioned as a peripheral device. Such a post-processing device includes a stapling device, a punching device, and a starching and binding device. Those devices are each arranged to bind copied sheets of paper as one bundle and work the bound sheets so that they are allowed to be filed.
Such the copying machine provided with the post-processing device, however, is limited in light of specification. For example, the post-processing device is generally located in a right place inside of the copying machine for the purpose of reducing the size of the copying machine or the installed area. That is to say, the post-processing device is located on the way of feeding paper or located on the side of a tray for receiving the ejected sheets of paper. Under the present condition, hence, the copying machine disallows the post-processing device to be located in any place desired by an operator.
Hence, an operator is required to load an original to a scanner unit as considering the location of the post-processing device and the direction of the image to be formed on the sheet. Such an operation is difficult-to-understand for an unfamiliar operator. It means that the known copying machine provided with the post-processing device is difficult-to-use for the operator. On the other hand, if the overall copying system is arranged so that the operator can locate the post-processing device in his or her desired place, the overall copying system is made larger in size and needs a large installed area.